The present invention relates to fuel flow regulating valves for regulating a fuel flow.
Such regulating valves are well known in the art. One of such fuel flow regulating valves is disclosed for example in the SRC publication no. 11305-5DO1 “An Electronic Regulator for Automotive Gaseous Fuels Applications”, S. Hill, M. Sulatisky, K. Young of Saskatchewan Research Concept, and H. Portman, U. Imhof of Dynetek Industries LTD, Canada. The electronic pressure regulator is based on a pilot-operated principle and uses an on/off high-speed solenoid valve for fuel metering. Electronic diesel and gasoline pressure regulators are normally bypass regulators where the exiting fuel is returned to the fuel tank. Since this is not possible in hydrogen or natural gas fuel systems, because the fuel tank is at a higher pressure than the regulator outlet pressure, it is desirable to regulate the inlet of the fuel metering system. Some diesel and gasoline pressure regulating systems throttle or otherwise control a high pressure pump. However, they need a pump to raise a fuel pressure to the pressure stored in an accumulator or fuel rail. This is not an option for gaseous fuel stored under high pressure, such as hydrogen or natural gas. Electronic air pressure regulators have been also used for various applications. However, they are allowed to vent excessive pressure to the atmosphere. Since the working fluid of this pressure regulator may be a combustible fuel, venting excessive working fluid (fuel) is not an option.